Weft correcting apparatus



Nov. 17, 1964 A. LEIMER ETAL 3,156,964

WEFT CORRECTING APPARATUS Filed Feb. 20, 1962 2 Sheets-Sheet l INVENTORS Awaer LIE/HER s/m/za mew/Iva:

United States Patent 3,156,964 'WEFT CORRECTING APPARATUS Albert Lehner, Beimlerstrasse 15, Augsburg, Germany, and Siegfried Erunner, Leitershofen, near Augsburg, Germany; caid Erunner assignor to said Leinier Filed Feb. 20, 1962, Ser. No. 174,499 Claims priority, appiication Germany, Feb. 25, 1961, E 20,658 8 Claims. (Cl. 26-513) The present invention relates to a manually or automatically controlled weft thread distortion correcting device capable of being used to provide a weft straightening effect in a woven fabric, and operative to obviate various disadvantages of weft correcting devices suggested heretofore.

A number of devices have been suggested in the past for use in weft correcting or straightening operations. These known devices have, in general, been capable of correcting only certain types of distortion, however, and have ordinarily not been suitable for the correction of weft distortions regardless of the shape and/ or direction of such distortion. Such limitations represent a substantial disadvantage since unforeseeable weft distortions may occur, e.g., wavy distortions. The weft correcting arrangements suggested heretofore have, moreover, been subject to the additional disadvantage that the apparatus, when accomplishing the correction, operates to either brake or accelerate portions of the fabric material; and the actual mechanisms employed to effect such braking or acceleration have ordinarily been such that the correction is distributed over an indefinite, and usually extensive, area of the fabric. Such extensive treatment of the fabric may have an adverse effect upon parts of the fabric which are about to enter, or which may have already left, the weft straightening apparatus; and the type of correction effected can thus adversely influence other portions of the fabric outside the weft correcting apparatus, and may in fact lead to the formation of new and undesired weft displacements in portions of the fabric spaced from the correcting appliance.

The various disadvantages discussed above are obviated, in accordance with the present invention by the provision of an improved apparatus for straightening weft threads in a run or web of woven cloth, said apparatus being characterized by a cloth treatment zone formed between two endless stretchable (e.g., rubber) bands, or between such a band and a backing plate, in conjunction with means operative, in the treatment zone, through which the cloth web passes, to effect a localized and adjustable compression of the rubber band or bands in such manner that various adjacent areas in the width of the bands are independently and differently compressed. Such variations in band compression cause the said bands to be variably stretched, as will be described, and this in turn causes corresponding portions of the cloth run being treated to be variably accelerated in the treatment zone, thereby to effect any desired correction.

The aforementioned stretching efiect of the rubber band or hands is independent of the speed of the cloth and remains in existence until the pressure applied to the band or bands is relieved and the rubber returns to its original thickness.

One embodiment of the invention, by way of example only, is illustrated in the drawings in which:

FIG. 1 is a diagrammatic perspective view of the invention;

FIG. 2 is an elevation of part of the arrangement of FIG. 1 to a larger scale;

FIG. 3 is a plan view; and

FIG. 4 is a diagrammatic View of part of a piece of cloth showing the manner in which the invention operates.

EdShfihl Patented Nov. 17, 1954 ice As shown in FIG. 1, a weft correcting apparatus constructed in accordance with the present invention may comprise an endless rubber band 1 supported on a pair of rollers 3 and 4, and cooperating with a further endless rubber band 2 supported on further rollers 6, 5 and 7. The rollers 4 and 5 are at the exit side of the apparatus and are driven at the same speed but in opposite directions, e.g., by a motor as illustrated in FIGURE 1. A roller 9 is provided between rollers 3 and 4. This roller 9 can also be driven if desired, and can moreover be adjustable toward and away from a roller 10 (to be described) in a manner, and by means of a structure, similar to that to be described hereinafter in reference to said roller 1t). The speed of the drive is such that the circumferential speed or surface speed of the rubber bands 1 and 2 corresponds to or is equal to the speed of travel of cloth run 8 in the direction of the arrow. The roller 9 functions as a contra-pressure roller.

A composite roller comprising parts or rolls 1%, 1t), it) etc., is mounted between rollers 5 and 6 at a position opposite roller 9. Each individual roll, 1t 10', 10" etc. can, as best illustrated in FIGURES 1 and 2, be moved toward or away from roller 9 by a lever 11 mounted on a pivot 13. The contra-pressure roller 9 is illustrated in plan in FIG. 3, as are also the rubber bands 1 and 2, and the opposing rolls 19, 10, 10" etc. Each lever 11, upon which a roll 10, 10, 16", etc. is rotatably mounted, is adapted to rotate about the pivot 13 (FIG. 2) and is integral with or connected to a further lever 12. Accordingly, as can be seen from FIG. 2, when pressure is exerted in the direction of the arrow 14- on lever 12, the rubber bands 1 and 2 are pressed together and the rubber molecules are displaced in the manner shown by the double headed arrow A,B. The cloth run 8 between the rubber bands 1 and 2, and in the region where the rubber is subjected to pressure between rolls 10, 10', 10" etc. and roller 9, is itself accordingly subjected to an accelerating effect.

The amount of acceleration effected in any particular portion of cloth web 8 is dependent upon the amount of rubber displacement in the directions A. and B, in the sections of bands 1 and 2 adjacent said particular web portion. As a result, the stretch in the bands, and the resultant acceleration in the cloth portion being treated, is dependent upon the amount of constriction of bands 1 and 2 and may accordingly be varied by varying the magnitude of the force exerted in the direction of arrow 14. As this force is increased, the distance between rollers 9 and 1G is reduced; and this in turn operates to increase the speed of the incremental portions of bands 1 and 2 between rollers 9 and 10, thereby in turn accelerating the warp of web 8 passing this particular spot. The closer the rollers 9 and 10 are placed together, the greater will be the accelerating effect; and this acceleration in the warp will in turn cause an acceleration of the weft in cloth web 8 to straighten or otherwise bring the weft into conformity with some desired weft position.

The band stretching, and resultant warp accelerating effect, that can be exerted by the rolls 10, 10', 10" etc. is indicated in FIG. 3 by the arrows X X X X X and X This accelerating effect is dependent upon the forces exerted on the rolls 10, 10', 1% etc. in the direction of arrow 14.

FIG. 4 shows, by way of example, a cloth run with weft threads having a straight line slant, the amount of which can be ascertained by the use of a weft thread distortion indicating appliance. The forces depicted by the arrows X X are, in such a case, graduated linearly in accordance with the assumed linear distortion or slant of the weft thread. The arrow X illustrates the maximum by a magnitude indicated at a+b 3 force applied in this assumed case, and X is intended to illustrate the application of zero force.

In the area where 15 :0, no significant acceleration takes place in the cloth run so that the distance between 1 ass-a for applying said localised varying pressure to said endless rubber band comprise a pressure roller consisting of a plurality of axially aligned rolls.

4. Apparatus for treating woven cloth to straighten the individual weft threads as indicated by the numerals 5 A wpft threads thereof including a first endless rubber a on the right of FIG. 4 remains constant. K

In the area of maximum applied force X maximum warp acceleration takes place in cloth web 8 so that the distance betwen the weft threads is increased in this area In the area where the lesser force X is applied, the warp acceleration in the cloth run 8 is also less, as indicated by a+b By thus varying and appropriately relating the forces applied to the several rolls 10, 10", etc., any shape of distortion of the weft threads can be corrected.

The basic concept of the present invention can also be practiced by utilizing a contra-pressure roller 9 which, rather than being continuous, takes the form of a plurality of individual cylinders or rolls 9, 9', 9", etc. (see FIGURE 1) corresponding to the rolls 10, 10, 10", etc., already described. With such a structure, the single force in the direction of arrow 14 can be replaced by a pair of forces applied symmetrically to and between any individual pair of opposed rolls. In either case, it is preferable for the individual rolls employed, such as 10, 10, 10", etc. to be somewhat barrel shaped in form to effect a smoother gradation of forces applied to adjacent portions of the rubber bands 1-2. Such a barrel shape for the individual rolls is depicted in FIGURE 3.

Since, as can be seen from FIGURE 3, the cloth web does not rest directly on any rollers, but is disposed between the bands 1 and 2, disadvantageous erratic changes in acceleration, which sometimes occur in the case of cloth runs or Webs resting directly upon rollers, are avoided. The use of stretchable bands 1 and 2 for variably accelerating adjacent portions across the width of cloth web 8 also assures that the several forces X X etc., applied to the several individual rolls, manifest themselves in a smoothly varying gradation in the acceleration efiect, thereby avoiding erratic or sudden changes in acceleration throughout the width of cloth web 8.

It should further be noted that the weft correcting apparatus and techniques of the present invention have no effect on the tension of the portions of the cloth web either in front of or behind the weft correcting device. Weft correction occurs within and is confined to the treatment zone between bands 1 and 2, and the desired weft correction can take place even if the cloth run arrives at and leaves the device at extremely low tension.

Having thus described our invention, we claim:

1. Apparatus for treating Woven cloth to straighten weft threads thereof including a first endless rubber band, support means for said band, means for applying a localised varying pressure to said band to cause variable stretching of a localized portion thereof, cloth support means including a second endless rubber band having a portion'extending closely adjacent to said localized portion of said first band, and means for feeding a woven cloth between said adjacent portions of the first and second rubber bands.

2. Apparatus as claimed in claim 1 in which said means for applying said localised varying pressure to said band includes means operative to apply varying pressures to said band along a line extending transverse to the feed direction of said cloth, said varying pressures varying in accordance with the amount of weft thread distortion in said woven cloth.

3. Apparatus as claimed in claim 1 in which said means band, support means for said band, means for applying a localised adjustable pressure to said band to cause stretching and relaxing of a localized portion thereof, said pressure applying means comprising a pressure roller consisting of a plurality of axially aligned rolls, means for adjusting the pressure applied by each roll, cloth support means in the form of a second endless rubber band, means for supporting a portion of said second endless rubber band in opposed relation to the localized portion of said first endless band which is subjected to said localised adjustable pressure, and means for feeding a length of woven cloth between said opposed portions of said first and second bands.

5. Apparatus as claimed in claim 4 in which said support means for said first and said second endless rubber bands comprise guide rollers, said pressure roller being disposed between a pair of said guide rollers for said first endless band, and means'for driving guide rollers of said first and second endless rubber bands.

6. Apparatus as claimed in claim 5 in which said guide rollers supporting said second endless rubber band includes a roller consisting of a plurality of axially aligned rolls. 7

7. Apparatus as claimed in claim 4 in which each of said axially aligned rolls of said pressure roller is barrel shaped.

8. Weft straightening apparatus for woven cloth comprising an endless band of stretchable material, means supporting said band for continuous closed loop movement along a preselected path, pressure means defining an elongated cloth treatment zone adjacent which an elongated portion of said band is continuously positioned during its said closed loop movement, means for applying different pressures to different localized parts of said elongated portion of said band to effect varying amounts of localized stretching at different positions in said elongated portion of said band thereby to variably accelerate corresponding portions of cloth in said treatment zone, and means for feeding a length of cloth through said elongated treatment zone in intimate contact with said varyingly stretched parts of said elongated band portion, said pressure applying means comprising means operative to effect a pressure gradient along said parts of said band in a direction extending transverse to the direction of said cloth feed.

References Cited by the Examiner UNITED STATES PATENTS 886,024 4/08 Wiebke 2669 1,107,771 8/14 Ezbelent 26-69 1,272,924 7/18 Doran 26-513 1,690,334 11/28 Durrant 265l.3 2,825,117 3/58 Evans etal 2618.6 X 2,972,795 2/61 Backer et al 26-69 X 3,007,223 11/61 \Vehrmann 26-18.6

FOREIGN PATENTS 14,453 9/34 Australia.

MERVIN STEIN, Primary Examiner.

RUSSEL C. MADER, DONALD W. PARKER,

Examiners. 

1. APPARATUS FOR TREATING WOVEN CLOTH TO STRAIGHTEN WEFT THREADS THEREOF INCLUDING A FIRST ENDLESS RUBBER BAND, SUPPORT MEANS FOR SAID BAND, MEANS FOR APPLYING A LOCALISED VARYING PRESSURE TO SAID BAND TO CAUSE VARIABLE STRETCHING OF A LOCALIZED PORTION THEREOF, CLOTH SUPPORT MEANS INCLUDING A SECOND ENDLESS RUBBER BAND HAVING A PORTION EXTENDING CLOSELY ADJACENT TO SAID LOCALIZED PORTION OF SAID FIRST BAND, AND MEANS FOR FEEDING A WOVEN CLOTH BETWEEN SAID ADJACENT PORTIONS OF THE FIRST AND SECOND RUBBER BANDS. 